SmMn2Ge2和GdMn2Ge2中的自发磁相变和场诱导的磁相变

在 1 0～ 80 0K的温度范围内用X射线衍射方法测量了SmMn2 Ge2 和GdMn2 Ge2 的晶格常数与温度的变化关系 .实验结果表明 :在各种类型的自发磁相变温度处观察到晶格常数的磁弹性异常现象 ;Mn Mn间的交换相互作用能不仅与晶格常数a有关 ,而且与晶格常数c有关 .此外 ,在 2 7T的脉冲强磁场中测量了SmMn2 Ge2 及GdMn2 Ge2 的磁致伸缩 ,在这 2种化合物中观察到了场诱导的一级磁相变 .

Spontaneous and field-induced magnetic phase transitionsin the intermetallic compounds SmMn2Ge2 and GdMn2Ge2

The temperature dependence of lattice constants a and c of intermetallic compounds SmMn2Ge2 andGdMn2Ge2 is measured in the temperature range 10～800 K by using the X-ray method. The magnetoelastic anomalies ofa and c are found at different spontaneous magnetic phase transitions. It is shown that the Mn-Mn exchange interactionsdepend not only on the lattice constant a but also on constant c. The magnetostriction of SmMn2Ge2 and GdMn2Ge2 ismeasured in the 27 T plus magnetic field. The field-induced magnetic phase transitions are found in these compounds.